Black Blade

{p/b}{p/r} Teach Black Blade to a creature if the creature's power is 4 or higher.
{p/b}{p/b}{p/b}{p/r}{p/r} Cast Black Blade at a target player, cursing that target. At the beginning of the cursed target's upkeep, that player takes 1 damage. This effect stacks to a maximum of 10.